Railway track circuits



March 17, 1936. H A P O 2,034,496

RAILWAY TRACK CIRCUIT S Original Filed Feb. 11, 1932 2 Sheets-Sfieet 1 Fag. Z.

IN VEN T OR.

Howard/1. Thompson.

By Q W HIS A TTORNE Y.

March 17, 1936. H. A. THCMPSON 2,034,496

RAILWAY T RACK CIRCUITS I I Original Filed Feb. 11, 1932 2 Sheets-Sheet 2 45 40 .Comflol of Swl'ich 5W INVENTOR.

Howa dA. Thompson y Q DZW HIS A TTORNE Y.

Patented Mar. 17, 1936 NETED STATES PATET OFFICE RAILWAY TRACK CIRCUITS Application February 11, 1932, Serial No. 592,255 Renewed November 20, 1934 30 Claims.

My invention relates to railway track circuits, and has for an object the provision of novel and improved means for expediting the release of a track relay when a vehicle enters the section of track with which the relay is associated.

A feature of my invention lies in providing for positive operation of a relay as a train enters a track section and shunts the usual track circuit. This positive action is especially useful in interlocking territory to release approach locking and other circuts on the closed circuit principle in contrast to the open circuit principle used heretofore at such locations. Other features of my invention will appear as the specification progresses.

I will describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view of one form of apparatus embodying my invention. Figs. 2, 3, 4, and are diagrammatic views of other forms of apparatus each of which also embodies my invention. Fig. 6 is a diagrammatic view of apparatus embodying my invention applied to a track section that may be entered from several directions, such, for example, as a track section including a crossover. Fig. 7 is a diagrammatic View of one form of apparatus embodying my invention, applied to a stretch of railway for which there is provided an approach locking circuit governing the operation of a railway switch. The release of the approach locking circuit is accomplished in Fig. '7 on the closed circuit principle without any additional apparatus over that required to expedite the release of the usual track relay.

Similar reference characters refer to similar parts in each of the several views.

Referring to Fig. 1, the reference characters I and I designate the rails of a railway track which are arranged by insulated rail joints 2 to form a track section AB through which trafiic normally moves in the direction indicated by an arrow. The track section AB is provided with a track circuit that includes the bonded rails of the section in the customary manner. A track battery 3 is connected across the rails l and l at the exit end of the section through a current limiting resistor 4. The battery 3 is so positioned in the circuit that its positive terminal is connected to the rail I and its negative terminal connected to the rail l as indicated by the plus and minus signs in Fig. 1. The track relay TR, which is a direct current neutral relay, is connected by the leads 5 and 6 to the rails l and l respectively, at the entrance end of the track section. It follows that with battery 3 connected to the rails, as shown in Fig. 1, current flows from positive terminal of battery 3 along the rail l through track lead 6, winding of the relay TR, '5 thence to the rail I by the track lead 5, and to the negative terminal of battery 3 to energize the relay TR with a given polarity.

An additional insulated joint 7 is placed in the rail i a short distance from the entrance of sec- 10 tion AB to form a short insulated rail section II. Around the insulated rail joint 1 there is connected an auxiliary battery 8 by a circuit that includes a resistance 9, and a front contact ll] of an armature I3 of relay TR. The battery 8 is so placed in this circuit that its positive terminal is connected to the short rail section II and the negative terminal to the rail l in advance of the insulated joint 1 as indicated by the plus and minus signs in the figure. It follows that normally no current will flow from the battery 8 except perhaps a small leakage current through the insulated joint 1, and the neutral relay TB is normally retained energized at a given polarity by current from the battery 3.

When the leading pair of wheels of a train entering the section AB from the left passes the insulated rail joints 2 and spans the short rail section II and the rail I, current is supplied from the auxiliary battery 8 through resistance 9, short rail section II, leading wheels and axle of the train, rail I, track lead 5, winding of relay TR, track lead 6, rail l wire l2, front contact ll) of armature I3, and to the negative terminal of the auxiliary battery 8. The flow of current 5 from the auxiliary battery 8 in the winding of relay TR is in a direction to oppose the current fiow supplied by the track battery 3, and thus there is a magnetic field established by the current supplied from the battery 8 that opposes the normal magnetic field established by the flow of current from battery 3. The resistance 9 and battery 8 are made such that the-current flowing from battery 8 is preferably equal to or greater than the current fiow established by the battery 3. There will result, therefore, a rapid dying away of the normal magnetic field created by the winding of relay TR and as the resultant field approaches the value of zero, the armatures l0 and I8 are caused to be released very so quickly after the leading pair of wheels of the train has passed over the insulated joints at the location A. The time required to release the armatures In and I 8 will be much less in this case than that ordinarily required where the track relay is shunted in the usual manner. As the track relay TR becomes deenergized and the front contact III of armature I3 opened, the battery 8 is rendered ineifective to further influence the relay TR. The rail section II being but a few feet in length, the leading pair of wheels of the train quickly advances past the insulated joint I and forms a shunt on the track relay TR in the usual manner to retain the track relay TR deenergized. The armature I8 of relay TR may be utilized to govern any control circuit desired. It is to be seen, therefore, that a quick release of the armature I8 of the relay TR is obtained by momentarily applying energy of reverse polarity across the traffic rails of the section upon the entrance of a train into the section. This energy of reverse polarity is obtained by means of a normally open circuit connected around an insulated rail joint located close to the entrance of the track section.

Where the insulated rail joints are staggered a half rail length as shown in Fig. 2, the auxiliary battery 8 is connected around the insulated joint 2 located in the rail I which in this instance is located in advance of the joint 2 in the rail I. The battery 8 is included in a normally open circuit similar to that described for Fig. 1, and thus normally supplies no current except possibly a small leakage current that may flow through the insulated rail joint. As soon as the first pair of wheels of a train entering the section AB passes over the insulated joint 2 in rail I, current flows from the positive terminal of the battery 8 through resistance 9 to rail I thence through the leading wheels and axle of the train to rail I, and then by the track lead 5 to the winding of the relay TR, track lead 6, rail I on the right-hand side of insulated joint 2, wire I2, front contact I!) of armature I3, and to the negative terminal of battery 8. As the direction of the flow of current from the battery 8 in the winding of relay TR is opposite to the direction of the normal flow of current from the battery 3, there will occur a rapid decrease in the normal magnetic field and the armatures I3 and I8 are quickly released in response to the train entering the section. As soon as the leading pair of wheels advances past the insulated joint 2 in the rail l the track relay TR becomes shortcircuited and will remain deenergized as long as any part of the train occupies the section AB. The circuit for the battery 8 being open at the front contact I!) as soon as the armature I3 is released, it is not again effective to energize the relay TR until the next train enters the section. In this form of apparatus, the track battery 3 for the section to the left of location A would preferably be connected to the rails I and I of its section with polarity reversed to that of the battery 3 for the section AB. From the foregoing discussion of the apparatus of Fig. 2, it will be apparent that a quicker release of the track relay TR is provided than is commonly obtained where the relay is shunted only as the train enters the section. This quick release is accomplished by momentarily applying energy of reverse polarity across the traflic rails as the leading pair of wheels of the train move into the section.

The form of apparatus shown in Fig. 3 difi'ers from that of Figs. 1 and 2 in that an auxiliary relay TX is provided. The normal track battery 3 will be connected to the rails I and I in the same manner pointed out in Figs. 1 and 2, and

the insulated rail joints 2 are staggered in the same manner indicated for Fig. 2. In the track lead 6 there is located a rectifier I4 so connected as to readily pass current flowing from the rail I to the winding of the relay TR but to substantially block the flow of current in the reverse direction. The track lead 5 is connected to the heel of an armature I5 of the auxiliary relay TX whose back contact is connected to the other terminal of the winding of the relay TR. One terminal of the winding of the auxiliary relay TX is connected to the track lead 6 and its opposite terminal is connected to the lead 5 through a rectifier I6 as will be readily understood by an inspection of Fig. 3. The rectifier I6 is so positioned as to readily pass current flowing from the lead 5 to the winding of relay TX and to substantially block the flow of current in the opposite direction. Normally, therefore, the auxiliary relay TX is uninfluenced by the normal flow of current from the battery 3 and remains deenergized completing the connection to the relay TR at the back contact of its armature I5, and relay TR is normally energized by the battery 3.

When a train moving in the normal direction of traffic enters the section AB of Fig. 3 and its leading pair of wheels pass over the insulated joint 2 in rail I, current flows from the battery 8 through resistance 9, rail I on the left-hand side of insulated joint 2, leading wheels and axle of the train, rail I, track lead 5, rectifier I6, winding of relay TX, track lead 6, rail I on the right-hand side of insulated joint 2, and wire I! to the negative terminal of battery 8. Relay TX is quickly picked up and the connection to the winding of relay TR opened at the back contact of its armature I5 allowing the normal magnetic field created by the winding of relay TR to rapidly die away with the result that the armature I8 is quickly released.

As long as the first pair of wheels of the train spans the rails I and l between the two staggered insulated rail joints, the relay TX remains energized by current supplied from the battery 8. The train by shunting the track battery 3 after it has passed the joint 2 in the rail I retains relay TR deenergized until the train vacates the section AB at which time relay TR becomes reenergized by current from battery 3. It follows that by applying energy of reverse polarity across the track leads 5 and 6 of Fig. 3 as a train enters the section AB, the relay TX is picked up and the relay TR deprived of all current and its armature I8 released to open any control circuit governed thereby. Thus the apparatus of Fig. 3 provides a quick release for the track relay TR the same as obtained by the apparatus for Figs. 1 and 2.

In Fig. 4, the apparatus is similar to Fig. 3 except the two neutral relays TR and TX with the two rectifiers I6 and I 6 are replaced by a direct current polarized relay TRI and an additional insulated rail joint I is located in the rail I a few feet in advance of the entrance of the section the same as shown for Fig. 1. In place of the additional insulated rail joint I in Fig. 4, the two insulated joints 2 may be staggered as shown for Figs. 2 and 3, and the auxiliary battery 8 connected around the joint in the rail I should it seem desirable to do so.

With relay TRI normally energized by battery 3, the polarity of its magnetic field is such as to cause the polarized armature I9 to seek the lefthand position, that is, the position shown in Fig.

4. In this form of apparatus of my invention, the polarized armature l 9 will be included in the control circuit governed by the armature M3 to hold closed the circuit as long as the relay TB! is energized with current of normal polarity and to open the circuit whenever the relay is energized with current of the reverse polarity in addition to the circuit being opened when the relay is deenergized and neutral armature I8 is down.

When the leading pair of wheels of a train passes the insulated rail joints 2 and spans between the short rail section II and the rail I, current flows from the battery 8 by a circuit similar to that previously described in detail to apply an energizing current to the relay TRI which is of a polarity reverse to that of the normal current from the track battery 3. The rapid decrease in the normal magnetic field of the relay will cause the neutral armature l8 to be quickly released to open the control circuit governed thereby. As the circuit from the battery 8 is not, in this form of apparatus, opened as the track relay becomes deenergized, the magnetic field created by the energizing of the winding of relay TRI by current from battery 3 will be shortly built up in the opposite direction to again pick up the neutral armature l8. Before the neutral armature I 8 is again picked up, the polarized armature I9 is reversed to its right-hand position and the circuit controlled by these armatures retained open although the relay TR! will be energized as long as the first pair of wheels of the train spans between the short rail section II and the rail I. As the first pair of wheels of the 'train passes the insulated rail joint I, batteries 8 and 3 both become ineifective to energize relay TRI due to the train shunt and its neutral armature !8 will then drop and remain down until the train has completely passed out of the section when relay TR! will become reenergized by battery 3.

In Fig. 5, a polarized relay TXI is connected directly across the track leads 5 and 6, and when energized by current of normal polarity as supplied to the trafiic rails by the track battery 3, its polarized armature 28 is held in the left-hand position, as shown in Fig. 5. The armature when held in engagement with its left-hand contact completes the connection from the track lead 6 to the Winding of the neutral relay TR which is then energized in the usual manner to hold its armature I8 in engagement with its front contact. As the first pair of wheels of a train passes the insulated .rail joints 2 at location A, the battery 8 quickly energizes the polarized relay TXI with current of reverse polarity causing its polarized armature 28 to be swung to the right-hand position thereby opening the connection to the relay TR and that relay deprived of all current with the result that its armature I8 is quickly released. The relay TXI remains energized by current from the battery 8 until the first pair of wheels of the train has moved off the short rail section II and the connection to relay TR is held open. From the time the train has advanced past the insulated joint I until it has completely vacated the section AB, the track battery 3 is short-circuited and relay TR retained deenergized. Again we see that the supplying of energy of reverse polarity across the trailic rails as the first pair of wheels of a train enters the section results in the track relay TR. being deenergized in a manner to cause a quick release of its armature l8.

In Fig. 6, the track section AB includes the crossover D leading from a track C. At the battery end of the section, an additional insulated rail joint 2| is located a few feet from the insulated joint 2 in the rail l to form a short rail section 22. At the relay end of the section, the insulated joint I is located in the rail l the same as described for Fig. 1. The auxiliary battery 8 is connected around the insulated joint 1 with its positive terminal connected to the rail section II and its negative terminal connected to the rail I as previously described. The positive terminal of the battery 8 is also connected by wire 23 to a rail 25 of the crossover D. Branching from the wire 23 is a wire 25 leading to the short rail section 22 so that this short rail section is also connected to the positive terminal of the battery 8. The auxiliary relay TX and the neutral track relay TR are connected to the track leads 5 and 6 through reciifiers l8 and I4, respectively, the same as described for the apparatus of Fig. 3, and the relay TX controls the connection to the relay TR at the back contact of its armature I 5.

A train upon entering the section AB of Fig. 6 from the left at the location A will complete the circuit for the battery 8 as soon as the leading pair of wheels passes the insulated joints 2 and cause the relay TX to become energized as described heretofore. The energizing of relay TX opens the connection to the track relay TR depriving it of all current with the result that its armature I8 is quickly released in response to the train entering the section. Should a train enter the section AB from the right at location B, the leading pair of wheels spanning between the short rail section 22 and the rail I completes a circuit for the auxiliary battery 8. This circuit can be traced from the positive terminal of battery 8 through resistance 8, wires 23 and 25, short rail section 22, Wheels and axle of the train to rail l thence by track lead 5 and rectifier It to the Winding of relay TX, track lead 6, and back to the negative terminal of the battery 8. It follows that the relay TX will function to effect a quick release of the relay TR in response to a train entering the section AB at the location B the same as is obtained when the train entered the section from the left at location A. Again, in the event the train enters the section AB from the left over the crossover D, the leading pair of wheels upon passing the insulated joints 26 and 21 completes a circuit for the battery 8 to the relay TX as will be readily understood by an inspection of Fig. 6, and relay TX is caused to function to bring about a quick release of the relay TR.

It is clear, therefore, that the apparatus of Fig. 6 provides means whereby energy of reverse polarity is applied to the track leads for the track relay to cause a quick release of that relay when a train enters upon the track section in any one of several different directions. Such an arrangement is particularly useful for applications to track sections within interlocking territory, as will be readily understood by those skilled in the art.

The same apparatus that provides a quick release for the track relay TR in Fig. 6 can further be used to give a positive action in response to a train entering the track section. In Fig. 6, the relay TS is the usual track repeater relay commonly provided at interlocking locations. The repeater relay TS is normally retained energized by current from the positive terminal X of any convenient source of current not shown, through front contact of armature l8 of track relay TR, wire 28, front contact of its own armature 29, winding of relay TS, and to the opposite terminal Y of the same source of currrent. The pickup circuit for the relay TS is the same as that just traced for the stick circuit up to the wire 28 and thence by wire 30, front contact of a relay TXS to be shortly described, wire 32, winding of relay TS, and to the terminal Y.

The additional relay TXS is provided with an energizing or pickup circuit that extends from terminal X of the source of current through the front contact of armature 33 of the relay TX, wire 34, back contact of armature 35 of relay TS, winding of relay TXS, and to the opposite terminal Y. With relay TXS once picked up, it is supplied with current by a stick circuit from the terminal X through the front contact of its own armature 35, wires 3? and 34, back contact of armature 35, winding of relay TXS, and to the terminal Y.

A train entering the section A--B in any one of the several directions described above causes relay TX to be energized by current supplied from the auxiliary battery 8. When relay TR is released, the circuit to the repeater relay TS is opened and that relay deenergized. During the interval relay TX is held energized after the relay TS becomes deenergized, the pickup circuit for the relay TXS is closed and that relay energized after which it is retained energized by its own stick circuit until the repeater relay TS is again picked up. To check that the relay TXS is operated each time the track section is entered by a train, the repeater relay TS can be reenergized only in the event the front contact of the armature iii of relay TXS is closed. The relay TXS is made slightly slow-releasing by connecting the rectifier 38 across the terminals of its winding in order that relay TS will have sufillcient time to pick up. It follows that the energizing of the relay TXS as the train enters the section AB is a positive operation based on the closed circuit principle and thus forms a reliable means for controlling the release of approach locking circuits at interlocking locations.

In Fig. '7 there is shown the apparatus of Fig. 6 applied to an approach locking circuit for a switch SW located in the section A-B. The circuits and the operation of the relays TX, TR, TS, and TXS are the same as just pointed out for the apparatus of Fig. 6 and it is thought need no further description except to point out that the pickup circuit for the track repeater relay TS includes a contact 39 operated by a lever L of an interlocking machine not shown, and which contact is closed when the lever L occupies its normal position. Traffic moving towards the switch SW from the left is governed by a signal S which will be controlled by the lever L in accordance with standard practice. The control circuits for the signal S are not shown as they form no part of my invention.

The relay GP checks the stop position of the signal S in accordance with the standard practice and approach relay AR is controlled by the track relay TR2 of an approach track section in the usual manner. The approach locking relay M governs the operation of the switch SW at the front contact of its armature M3 in accordance with standard practice and it is deemed suificient for this application to point out that when the relay M is energized and the front contact of armature 40 closed, switch SW can be moved from one position to the other but when relay M is deenergized and the armature 40 down, the switch SW is locked against movement.

Locking relay M is normally retained energized by virtue of a stick circuit from battery terminal X through front contact of armature 4! of relay GP, front contact of armature 42 of relay AR, front contact of its own armature 43, winding of relay M, and. to the terminal Y. With the signal S cleared for the passage of a train towards the switch SW, the relay GP is deenergized and the approach locking relay M, in turn, deenergized to prevent movement of the switch SW. As the train enters the section A-B, the relay TX is picked up and the track relay TR released in the manner previously pointed out. The deenergizing of relay TR opens the circuit to the repeater relay TS and it, in turn, is deenergized. While relay TX is picked up and relay TS is down, the relay TXS becomes energized and then is held closed by its stick circuit. As relay TXS becomes energized, the pickup circuit for the approach locking relay M is closed from terminal X, front contact of armature 4] of relay GP as that relay is now energized, front contact of armature 44 of relay TXS, winding of relay M, and to the terminal Y. As the reenergizing of the approach locking relay M is brought about by the picking up of the relay TXS, it follows that the release of the approach locking is acccmplished on the closed circuit principle, the utility of which will be readily understood to all those skilled in the art. TE is the usual time element relay provided for releasing the approach locking relay M under certain traffic conditions. However, it is thought its control needs no further description in the present specification as it forms no part of my invention.

While the arrangement of Fig. 3 is employed in Figs. 6 and '7, it will be readily understood that the arrangement used in Figs. 4 and can equally as well be applied in Figs. 6 and 7.

Although I have herein shown and described only certain forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, atrack section, a circuit controlling armature having a biased position and. an operated position, a track circuit including a current source adapted to normally supply across the traffic rails of the section energy of a given polarity, a winding connected across the trafiic rails' responsive to energy of said given polarity to establish a magnetic field for holding said armature in its operated position, and an auxiliary track circuit having a current source normally inactive adapted to supply across the traffic rails energy of a polarity reverse to said given polarity in response to a train entering the track section for causing said winding to annul the established magnetic field to permit the armature to be quickly released from its operated position as the train enters the section.

2. In combination, a track section, a circuit controlling armature having a biased position and an operated position, a track circuit including a current source adapted to normally supply across the trafiic rails energy of a given polarity, a winding connected across the traffic rails responsive to energy of said given polarity to establish a condition for normally holding said armature in its operated position, and an auxiliary track circuit including a current source normally inactive adapted to supply across the trafiic rails energy of a polarity reverse to said given polarity in response to a train entering the track section for causing said Winding to annul said established.

condition to permit the armature to be quickly moved from its operated position to its biased position after the train has entered the section.

3. In combination, a track section, a circuit controlling device having a biased position and an operated position, a track circuit including a current source adapted to constantly supply across the trafiic rails of the section energy of a given polarity, means connected across the traffic rails responsive to energy of said given polarity to establish a condition for normally holding said circuit controlling device in its operated position, an insulated rail joint in a traific rail at the entrance end of the track section, and a normally open circuit including a current source connected around said insulated rail joint arranged to supply across the two trafiic rails energy of a polarity reverse to said given polarity in response to a train entering the section for causing said means to annul said established condition to permit the circuit controlling device to be released from its operated position.

4. In combination, a track section, a relay having an armature biased to a released position and a winding for moving the armature to an operated position, track leads for Connecting the winding across the two trafiic rails of the section, a track circuit including the traific rails of the section and a current source adapted to normally supply energy of a given polarity across the track leads for energizing the winding to hold the armature in its operated position, and an auxiliary circuit effective only as a train enters the section to supply energy of a polarity reverse to said given polarity across said track leads to deenergize the winding for causing a quick release of the armature from its operated position.

5. In combination, a track section, a relay having an armature biased to a released position and a winding for moving the armature to an operated position, track leads for connecting the winding across the two traific rails of the section, a track circuit including the traific rails of the section and a current source adapted to normally supply energy of a given polarity across the track leads for energizing the winding to hold the armature in its operated position, and a normally open circuit closed in response to a train entering the section adapted to supply energy of a polarity reverse to said given polarity across said track leads to deenergize the winding for causing a quick release of the armature from its operated position.

6. In combination, a track section, a circuit controlling armature having a biased position and an operated position, track leads connected to the opposite traffic rails of the section, a track circuit including the trafic rails and a current source adapted to supply across the track leads energy of a given polarity, means connected to said track leads responsive to energy of said given polarity to establish a magnetic field to hold said armature in its operated position, and an auxiliary circuit connected to one of said tramc rails effective only as a train enters the section to supply across the track leads energy of a polarity reverse to said given polarity for causing said means to nullify the established magnetic field to permit the armature to be quickly released from its operated position.

'7. In combination, a track section, a relay having an armature biased to a released position and a winding connected across the trafiic rails of the section for moving the armature to an operated position, a track circuit including the trafiic rails and a source of current for normally energizing the winding with current of a given polarity to normally hold the armature in its operated posi-v tion, an insulated rail joint located in one of the traffic rails, and an auxiliary circuit including a source of current and a contact closed by the armature in its operated position connected around the insulated rail joint and arranged to momentarily supply to the winding as a train enters the section current of a polarity reverse to said given polarity to nullify the normal energization and thereby permit a quick release of the armature from its operated position.

8. In combination, a track section, a relay having an armature biased to a released position and a winding connected across the traffic rails of the section for moving the armature to an operated position, a track circuit including a current source connected across the traffic rails for normally energizing the winding with current of a given polarity to normally hold the armature in its operated position, a normally open auxiliary connected across the traffic rails for normally energizing the winding with current of a given polarity to normally hold the armature in its operated position, a normally open auxiliary circuit including a source of current, means for rendering said auxiliary circuit effective to supply to the winding current of a polarity reverse to the given polarity in response to a train entering the section to nullify the normal energization and thereby permit a quick release of the armature from its operated position, and means to render the auxiliary circuit ineffective as the armature is released from its operated position.

10. In combination, a track section, a relay for said track section having an armature biased to a released position and a winding for moving the armature to an operated position, a track circuit including the traffic rails of the section and a current source adapted to normally supply energy of a given polarity to said winding to move the armature to its operated position, and a normally open auxiliary circuit rendered active under certain traffic conditions of the track section to momentarily supply to said winding energy .of a polarity reverse to said given polarity to counteract the normal supply of energy for causing a quick release of the armature from its operated position.

11. In combination, a track section, a circuit controlling device having a circuit closing position and a circuit opening position, a track circuit including a current source adapted to normally supply across the trafiic rails of the section current of a given polarity, polarized means connected across the traiilc rails energized by current of said given polarity to normally hold said circuit controlling device in its circuit closing position, and an auxiliary track circuit normally inactive rendered active in response to a train entering the section to supply across the traflic rails current of a polarity reverse to said given polarity to nullify the effect of the current of the first mentioned track circuit and to energize the polarized means to move the circuit controlling device to its circuit opening position.

12. In combination, a track section, a circuit controlling device having a circuit closing position and a circuit opening position, a track circuit including a current source adapted to normally supply across the trafiic rails of the section current of a given polarity, polarized means connected across the traffic rails energized by current of said given polarity to normally hold the circuit controlling device in its circuit closing position, an insulated rail joint located in a traffic rail of the section, and a normally open auxiliary circuit connected around said joint arranged to supply across the trafiic rails of the section current of a polarity reverse to said given polarity in response to a train entering the section to render the first mentioned track circuit inefiective and to energize the polarized means to move the circuit controlling device to its circuit opening position.

13. In combination, a track section arranged to be entered by a train at any one of several points, an armature having a biased position and an operated position, a source of current adapted to normally supply across the traffic rails of the section current of a given polarity, means connected across the trafi'lc rails influenced by current of said given polarity to normally hold the armature in its operated position, and a normally open auxiliary track circuit including a current source having one terminal connected to a trafiic rail at each entrance point of the section and arranged to supply across the traffic rails current of a polarity reverse to said given polarity in response to a train entering the section at any one of said several points to nullify the normal influence on said means and thereby quickly release the armature from its operated position.

14. In combination, a stretch of trafiic rails arranged into a track section, an insulated joint located in one traffic rail slightly in advance of the entrance of the track section, an armature having an operated position, a winding adapted when energized to move the armature to its operated position connected across the traffic rails in advance of the insulated rail joint, a normally open circuit including a current source connected around the insulated rail joint arranged to be closed by a pair of train wheels and axle spanning the traffic rails between the entrance of the section and the insulated joint to energize the winding, a stick relay having a pick-up circuit closed by the armature in its operated position and a stick circuit controlled by other means, and a signaling circuit controlled by the stick relay.

15. In combination, a track section containing a railway switch, an approach locking relay, means for preventing the operation of said switch unless said relay is energized, an insulated rail joint located slightly in advance of the entrance of the track section, an armature having an operated position, a winding adapted when energized to move the armature to its operated position connected across the traflic rails in advance of said insulated joint, a normally open circuit including a current source connected around said insulated joint arranged to be closed by a pair of train wheels and axle spanning the traflic rails between the entrance of the track section and said insulated joint to energize the winding, and a circuit closed by the armature in its operated position to energize the approach locking relay.

16. In combination, a railway track, insulated rail joints located in the traffic rails of the track to form a track section, a pair of relays connected across the rails of said section, asymmetric units associated with said relays and arranged to pass current of one polarity to the winding of one relay and not to the other and to pass current of the opposite polarity to the winding of said other relay and not tothe winding of said one relay, a source of current connected with the traffic rails of said section to supply current of the polarity passed to said one relay to normally energize that relay, means effective at times to supply to the trafiic rails current of the polarity passed to said other relay to energize that relay, and a back contact of said other relay interposed between one of the traffic rails and the winding of said one relay whereby said one relay is released as said other relay is picked up.

17. In combination, a railway track, insulated rail joints located in the traffic rails of the track to form a track section, a pair of relays connected across the rails of said section, asymmetric units associated with said relays and arranged to pass current of one polarity to the winding of one relay and not to the other and to pass current of the opposite polarity to the winding of said other relay and not to the winding of said one relay, a source of current connected with the tranic rails of said section to supply current of the polarity passed to said one relay to normally energize that relay, a normally open auxiliary circuit connected around an insulated joint located at the entrance of the section and arranged in such a manner as to supply across the traffic rails as a train enters the section current of the polarity passed to said other relay for energizing said other relay, and a back contact of said other relay interposed between one of the traflic rails and the winding of said one relay whereby said one relay is quickly released as a train enters the section.

18. In combination, a railway track, insulated rail joints located in the trafilc rails of the track to form a track section, a first track relay connected across the rails of the section, a source of current connected across the rails of the section to supply current for normally energizing said relay and arranged to supply current of a given polarity, a second track relay connected across the rails of the section, an asymmetric unit associated with said second relay and arranged to pass only current of a polarity opposite said given polarity to the winding of the second relay, an auxiliary circuit connected around one of the insulated joints at the entrance of the section and arranged in such a manner as to supply across the traific rails as a train enters the section current of said opposite polarity for energizing said second relay, and a back contact of said second relay interposed between one of the traflic rails and the winding of the first track relay.

19. In combination, a railway track, insulated rail joints located in the traflic rails of the track to form a track section, a first track relay connected across the rails of the section, a source of current connected across the rails of the section to supply current for normally energizing said relay and arranged to supply current of a given polarity, a second track relay connected across the rails of the section and having a back contact included in the connection between said first track relay and one of the track rails, an asymmetric unit associated with said second relay and arranged topass only current of a polarity opposite said given polarity to the winding of the second relay, an auxiliary circuit connected around one of the insulated joints at the entrance of the section and arranged in such a manner as to supply across the traffic rails as a train enters the section current of said opposite polarity for energizing said second relay, and signaling means controlled jointly by said two track relays.

20. In combination, a railway track, insulated rail joints located in the trafic rails to form a track section, another insulated rail joint located in one rail slightly in advance of the entrance of the section, an auxiliary track relay connected across the trafiic rails ahead of said other rail joint, an asymmetric unit associated with said relay and arranged to pas to the winding of said relay current of a given polarity only, a source of current connected around said other rail joint and arranged in such a manner that the spanning 01" the two traffic rails between the entrance of the section and said other rail joint by the leading pair of wheels and axle of a train is effective to supply across the trafiic rails current of said given polarity to energize said relay, and signaling means controlled by said relay.

21. In combination, an insulated railway track section including a track switch, an approach locking relay having a first and a second position, means for permitting operation of the switch when said relay occupies its first position only, a normally closed track circuit including the trafiic rails of the section and a track relay and arranged to be supplied with current of a given polarity, an auxiliary track relay connected across the traffic rails of the section, an asymmetric unit associated with the auxiliary relay and arranged to pass to the winding of said relay only current of the polarity opposite said given polarity, a source of current connected around an insulated rail joint at the entrance of the section and arranged in such a manner that the spanning of the two trafiic rails at the entrance of the section by the leading pair of wheels and axle of a train is effective to supply across the trafiic rails of the section current of said opposite polarity for energizing the auxiliary relay, and means controlled by a front contact of the auxiliary relay and rendered effective by the deenergizing of the normally energized track relay for operating the approach locking relay to said one position.

22. In combination, an insulated railway track section including a track switch, another insulated rail joint located slightly in advance of the entrance of the section, a normally energized approach locking relay having a front contact controlling the operation of said switch, a normally closed track circuit including the traffic rails of the section and a track relay and arranged to be supplied with current of a given polarity, an auxiliary track relay connected across the traffic rails ahead of said other rail joint, an asymmetric unit associated with the auxiliary relay and arranged to pass to its winding only current of the polarity opposite said given polarity, a source of current connected around said other rail joint and arranged in such a manner that the spanning of the two traflic rails between the entrance of the section and said other rail joint by the leading pair of wheels and axle of a train is effective to supply across the traffic rails current of said opposite polarity to energize the auxiliary relay, and means controlled jointly by the auxiliary relay and said track relay and rendered eifective by the picking up of the auxiliary relay and the releasing of the track relay for energizing the approach locking relay.

23. In combination, a track section, a circuit controlling armature having a biased position and an operated position, a track circuit including a current source adapted to normally supply current across the traffic rails of the section a winding connected across the trafiic rails responsive to current from said track circuit to establish a magnetic field for holding the armature in its operated position, and an auxiliary track circuit normally inactive adapted to be rendered active in response to a train entering the section to supply across the traffic rails current for causing said winding to nullify the normally established magnetic field and thereby permit the armature to be quickly released from its operated position as the train enters the section.

24. In combination, a track section, a circuit controlling armature having a biased position and an operated position, a track circuit including a current source adapted to normally supply current across the trafiic rails of the section, a Winding connected across the traffic rails responsive to current from said track circuit to establish a magnetic field for holding the armature in its operated position, and an auxiliary track circuit normally ineffective to apply a potential across said trafiic rails and rendered effective in response toa train entering the section to apply such potential across said rails for causing said winding to nullify the normally established magnetic field and thereby permit the armature to be quickly released from its operated position as the train enters the section.

25. In combination, a section of railway track, a main source of current connected across the rails of said section, a track relay having a winding receiving current from said rails, an auxiliary source of current, and means effective when a train enters said section for supplying said relay winding with current from said auxiliary source in a direction opposed to that in which current is supplied thereto from said main source whereby the release of said track relay will be expedited.

26. In combination, a track section, a track circuit for said section including a source of current, a track relay having a winding normally energized from said track circuit, and an auxiliary track circuit eifective upon the entry of a train int-o said section for supplying current of reverse relative polarity to said track relay winding for opposing the. normal energization thereof whereby the release of said relay will be expedited.

27. In combination, a track section, a track circuit for said section including a source of current, a track relay having a winding normally energized from said track circuit, and an auxiliary track circuit effective upon said section becoming shunted for supplying current of reverse relative polarity to said track relay winding for opposing the normal energization thereof whereby the release of said relay will be expedited.

28. In combination, a track section, a track circuit for said section including a source of current, a track relay having a Winding normally energized from said track circuit. and an auxiliary circuit efiective when said section becomes occupied by a vehicle for supplying current of reverse relative polarity to said track relay winding for opposing the normal energization thereof whereby the release of said relay will be expedited.

29. In combination, a track section, a track circuit for said section including a source of current, a track relay having a winding receiving current from said track circuit and adapted to be normally energized by said current, and an auxiliary circuit efiective when said section becomes occupied by a vehicle for supplying a second current to said track relay winding in such manner as to oppose the normal energization thereof 10 whereby the release of said relay will be expedited.

30. In combination, a track section, a track circuit for said section including a source of current, a track relay having a winding energized with current of normal relative polarity from said track circuit, and means for at times supplying said track relay winding with an additional cur-' 

